1. Field of the Invention
The present invention relates generally to synthesizers, and particularly to a programmable CMOS-based nonlinear function synthesizer that allows for the nonlinear function to be approximated by summation of hyperbolic tangent (tan h) functions via different arguments.
2. Description of the Related Art
Despite its limited accuracy, it is very well known that analog nonlinear signal processing is much faster than its digital counterpart. This justifies the use of analog nonlinear signal processing in applications where speed, not the accuracy, is the major concern. Such applications cover a wide range including, but not limited to, medical equipment, instrumentation, analog neural networks and telecommunications. Therefore, over the years, several approaches have been reported for synthesizing analog nonlinear functions. These approaches suffer from at least the following disadvantages. Firstly, only one or two functions can be realized, and secondly, the designer must use piecewise linear approximations to approximate the required nonlinear function.
Thus, a programmable CMOS-based nonlinear function synthesizer solving the aforementioned problems is desired.